The present invention relates to the field of audio loudspeakers, and more particularly to vehicular speakers of a popular compact size category directed to but not restricted to after-market replacement units.
Speakers are categorized mechanically by outside basket dimensions and characterized functionally by diaphragm size since generally low frequency performance is determined mainly by diaphragm area and excursion capability, i.e. the volume of air moved by the diaphragm acting as a piston.
Vehicular speakers are generally designed to mechanically fit a particular mounting pattern used by vehicle manufacturers, typically including a main cutout and three, four or six surrounding mounting holes, dimensioned according to standards originating from different world regions. Replacement speakers are generally required to fit the mounting pattern and space originally provided in the vehicle, preferably without any extra drilling or other rework of the vehicle.
As is conventionally known, the Japanese Industrial Standards Committee (JISC or JIS) is a Japanese agency that establishes and maintains standards for equipment and components. Moreover, Deutsches Institut fxc3xcr Normung e.V. (DIN) is the German Institute for Standardization. Together with its subsidiaries, DIN is dedicated to providing the whole range of services that support the development, distribution, and application of standards.
Round speakers having basket diameter in the 6xe2x80x3 to 7xe2x80x3 size range are in extremely high quantity vehicular usage in the U.S. and throughout the world. Most of these are made to either a JIS Japanese standard that specifies 6.18 inches (157 mm) diameter or a DIN German standard used in Europe that specifies 6.69 inches (170 mm) diameter.
Other key dimensions found in speakers made to these standards are shown the following table:
Manufacturers, distributors and dealers providing replacement vehicular speakers are ordinarily required to handle two different speaker models, one for each of these standards, and each having its corresponding mounting pattern, depending on the vehicle make, year and model, even though these dimensions
The DIN version is too large to fit into a JIS mounting pattern without extensive mechanical rework of the vehicle panel.
The JIS version, being the smaller of the two, has less diaphragm area and suffers a corresponding disadvantage regarding bass performance; this rules out the approach of simply mounting the smaller JIS speaker in the larger DIN mounting pattern with some form of mechanical adaptation.
A true dual-mounting-standard unit able to replace either of these types in a fully satisfactory interchangeable manner would yield substantial cost savings to manufacturers, distributors and dealers by reducing the inventory normally required to support these two slightly different types. The dual-mounting-standard replacement would be required to at least equal the bass performance of the larger sized DIN type while being able to mount readily in the smaller-sized JIS mounting pattern as well as in the larger-sized DIN mounting pattern.
The two major problems addressed by the present invention can be summarized as follows:
1) the JIS mounting problem: when the JIS smaller-sized speaker basket is fitted with a larger DIN-sized cone, the JIS mounting holes are no long available, being covered by the surround suspension flange and thus the holes are no longer available without degradation of the surround flange and its adhesive fastening to the basket flange, therefore an alternate fastening method is required for mounting the speaker to a JIS-configured vehicle panel: and
2) the DIN mounting problem: the four holes in the DIN mounting pattern fall directly on the diameter of the JIS basket, complicating mounting to a DIN-configured panel.
U.S. Pat. No. 5,867,583 to inventors Hazelwood, Espiritu and Jorgensen for TWIST-LOCK MOUNTABLE VERSATILE LOUDSPEAKER MOUNT is incorporated by reference into the present disclosure. The ""583 patent discloses a versatile JIS/DIN compatible dual-standard speaker that addresses the JIS mounting problem by utilizing an adaptor ring that mounts to a JIS-configured panel with screws and that is formed to provide four lock tabs by which the speaker basket is attached in a twist-lock/snap manner via rim slots, thus the speaker can be installed and removed without screws. ""583 addresses the DIN mounting problem (a) in the same manner, making the adaptor ring large enough to also provide DIN-configuration mounting holes or (b) by notching the speaker rim in four places and bridging each notch with a metal saddle clip that enables a self-tapping mounting screw to secure the rim to the DIN panel.
The present disclosure departs from ""583 in proposing a xe2x80x9cdual-standard replacement speakerxe2x80x9d utilizing alternative novel solutions to the JIS and DIN mounting problems that may be applied to a plastic basket as well as to a metal basket, and that utilize screw fastenings exclusively rather than snap/twist-lock tabs and/or saddle clips.
The ""583 patent cites as other examples of loudspeaker mounting systems that directed to quick mounting of compact round speakers in cut-outs of various existing panels: U.S. Pat. No. 4,815,558 to Krainhofer, assigned to U.S. Philips Corp., and 4,852,178 to Inkman et al, assigned to Motorola, Inc. These, while not necessarily directed expressly to dual-standard dual-standard compatibility, are of interest in disclosing quick-fastening speaker retaining assemblies comprising an intermediate support member such as a plate fitted with a plurality of latched posts which become engaged with a ring frame placed over the speakers and rotated to retain the speaker against the frame and the plate in a twist-lock manner.
It is a primary object of the present invention to provide a versatile mounting system for a dual-standard replacement speaker that enables convenient mounting into either of two slightly different-sized mounting patterns, including the main cutout and screw holes, such that the dual-standard replacement speaker can readily replace either of two different and ordinarily non-interchangeable speaker types.
It is a further object that the dual-standard speaker be made to provide a level of performance quality that equals or exceeds that of either of the two original speaker versions, particularly with regard to low frequency performance.
It is an object to provide, as a particular embodiment of the invention, a dual-standard round speaker for replacing vehicular speakers in the 5xe2x80x3 to 6xe2x80x3 range, that can be readily mounted into either of two popular speaker-to-vehicle mounting versions: the Japanese JIS version and the European DIN version.
It is another object to provide a replacement vehicular speaker with a rim configuration and a diaphragm surround suspension configuration that provides a ratio of effective diaphragm diameter to outside basket diameter that is higher than such ratio found in conventional speakers of known art.
It is a further object to solve both the JIS and the DIN mounting problems of a dual-standard speaker in both plastic and metal speaker basket implementations.
The above mentioned objects have been accomplished by the subject speaker of the present invention by utilizing an oversized diaphragm, intended for the larger of the two speaker versions, specially mounted on a basket intended for the smaller of the two speaker versions, with special mounting to the basket rim that ensures full diaphragm excursion.
The basket may be stamped from metal, similar to the conventional JIS speakers, or it may be cast from metal or molded from suitable plastic material: in any cases the nominal outside diameter will be made 157 mm so that the small size remains compatible with the JIS mounting hole array.
To enable mounting to a JIS-configured panel, an annular doubly-flanged sheet metal adaptor ring is formed with four raised regions at DIN mounting hole locations near the outer diameter, each configured with a hole, preferably extruded, that is threaded to engage a achene screw. The adaptor ring is also configured with an array of four mounting screw clearance holes in a JIS polar array pattern, offset from the four threaded holes in the raised regions, by which the adaptor ring is first secured by four self-tapping screws to the JIS-type panel, following which the plastic or metal basket is attached to the ring via the four relatively small sized machine screws. For mounting to a DIN-configured panel, the adaptor ring is not used: the plastic basket is configured with four extending ears providing clearance mounting holes at DIN mounting locations for self tapping screws which secure the basket to the DIN-type panel.
In the case of a metal basket, in a preferred embodiment the outer basket rim is configured with four notches cut out and extending ears with holes to accommodate self-tapping screws, located at DIN mounting locations.
In both plastic and metal implementations, the ears are made such that, particularly for JIS mounting where they are not needed, they can be snapped off and removed if necessary for clearance in tight surroundings.
Referring to TABLE 1, it is estimated that the 119.3 mm DIN cone provides an effective air piston with about 17% more area than the 111.8 mm JIS(a) cone. Practice of the present invention has enabled the cone size to be increased to at least 124 mm, thus providing about 8% more effective area than the DIN cone.